The invention relates to a device for receiving and dispensing a coatable material, comprising a sleeve-shaped receiving element, on the open delivery end of which a closure cap can be detachably pushed on and in which there is arranged a piston-shaped element, which is secure against rotation and is displaceable in longitudinal direction up to the delivery end and which is provided with an internal thread and carries the coatable material, the element being displaceable by an externally operable socket-shaped rotary grip provided at the other end of the receiving element, wherein the rotary grip comprises a screw spindle which is rotatably mounted in a passage opening in the sleeve base of the receiving element and held in axial direction and which co-operates with the internal thread of the piston-shaped element, wherein sealing means are provided for sealing the passage opening.
A device of that kind of the applicant has been known for a long time, for example in the form according to German specification 21 39 123 B2. Such a known glue stick comprises a cylindrical sleeve, the open delivery end of which is provided with a detachable closure cap in the case of non-use for the purpose of avoiding drying out of the glue mass disposed in the sleeve. The glue mass within the sleeve is cast into a piston-shaped element and together with this is held in the sleeve to be secure against rotation and arranged to be displaceable in the longitudinal direction of the sleeve, wherein, for displacement, the piston-shaped element is provided in the centre with an internal threaded bore in which a threaded spindle engages, the spindle extending almost over the entire length of the sleeve and thus also extending through the glue mass and integrally transitioning at the end into a knurled, nut-shaped rotary grip, which is rotatably mounted at the other end of the sleeve and protrudes outwardly of the sleeve at the foot thereof and enables manipulation of the device, in that, with the sleeve firmly held, the rotary grip is turned in one or the other direction so that the piston-shaped element and the glue mass connected therewith move relative to the sleeve in one or the other direction and enable either dispensing of the glue or retraction of the glue mass into the sleeve.
This known device has proved itself to be best for a long time, since an easily handled and at the same time very sturdy object is made available. However, since the device is provided in the region of the passage opening in the sleeve base with sealing means in order to avoid drying out of the glue mass, it has proved in practice that on retraction of the piston-shaped element an excess pressure can build up in the region behind the piston-shaped element in the sleeve-shaped receiving element and can frequently have the consequence that the coatable material is quasi popped off the piston-shaped element, whereby the device is unusable.
It is accordingly the object of the invention to s o improve a device according to the category that, without impairment of the sealing function, detaching of the coatable material from the piston-shaped element is reliably avoided.
According to the invention this object is met in the case of a device of the kind designated in the introduction in that an encircling sealing element is arranged radially outside the passage opening in the sleeve base and bears against the sleeve base and the associated end face of the rotary grip, that at least one ventilating opening is provided in the sleeve base radially within or in the region of the sealing element and that spacer means, which in the operative position thereof in at least one defined rotational setting enlarge the spacing between the sleeve base and the end face of the rotary grip, are provided at the sleeve base and/or at the end face of the rotary grip.
In the case of such a design of the invention an excess pressure build up in the sleeve-shaped receiving element in the region between the piston-shaped element and the sleeve base when the piston-shaped element is rotated back is avoided without thereby impairing the sealing function of the device. At least once per revolution the spacer means move into their operative position and enlarge the spacing between the sleeve base and the end face of the rotary grip so that the sealing element is transiently relieved and air can escape through the ventilating opening in the sleeve base, so that a build up of excess pressure does not occur. On further rotation of the rotary grip relative to the sleeve-shaped receiving element the spacer means move out of function again so that the necessary sealing function is guaranteed, i.e. the ventilating opening is sealingly closed by the sealing element disposed back in function. Since the ventilating opening during the rotating back of the piston-shaped element is freed only intermittently, several ventilating openings of that kind can also be provided in accordance with the size of the particular device.
In order to facilitate manipulation of the device it is advantageously provided that the spacer means are formed so that they go out of their operative position automatically. If, for example, the rotary actuation of the rotary grip relative to the sleeve-shaped receiving element by the user ends in exactly the operative position of the spacer means, these then move out of their operative position automatically so that the full sealing function is guaranteed.
In an embodiment which is constructionally particularly advantageous the spacer means are formed by detent projections, which are arranged on a common circumference, at the sleeve base and at the end face of the rotary grip. When the socket-shaped rotary grip is turned, the dog-like detent projections hit against one another, whereby the spacing of the sleeve base and rotary grip is transiently increased and the seal is relieved for this instant, so that air can exit through the ventilating opening.
In that case the detent projections are preferably formed to be inclined in such a manner that in their operative position they are disposed in an unstable contact position. It can thereby be achieved in simple manner that the detent projections do not remain in their operative position, which would impair the sealing function.
The detent projections are preferably arranged radially outside the sealing element and the sealing element is constructed as an annular seal.
In a further preferred constructional embodiment the sleeve base is formed to be inclined inwardly in step-shaped manner, wherein the detent projections are provided in a first, outer encircling step and the ventilating opening and sealing element are provided in a more inwardly disposed second step. By virtue of this design the afore-mentioned elements are arranged in the interior of the device and thus protected against the outside.